How are endemic and widely distributed bromeliads responding to warming temperatures? A case study in a Brazilian hotspot

Abstract

The increase in mean global temperature is causing extensive changes in ecosystems. However, little is yet known about the heat tolerance of neotropical plant species. Here, we investigate heat tolerance variation in both restricted and widely distributed bromeliad species co-occurring in campo rupestre, a megadiverse ecosystem in central and eastern Brazil. We determined the heat tolerance of the photosynthetic apparatus using chlorophyll fluorescence measurements to test if the endemic species Vriesea minarum is more heat sensitive than two widely distributed species, Vriesea bituminosa and Aechmea nudicaulis. Furthermore, we tested if the distinct photosynthetic metabolisms of the species, sun exposure, and rainfall seasonality of campo rupestre influence this outcome. Our results show that, contrary to our expectations, the endemic campo rupestre species did not show the greatest heat sensitivity, but did have one of the lowest heat tolerance plasticities. The CAM bromeliad A. nudicaulis was more heat tolerant than the other bromeliad species, but both heat tolerance and its plasticity are highly affected by sun exposure and the rainfall seasonality of campo rupestre. The low values and plasticity of V. minarum thermal tolerance could indicate that the threat of global warming could be greater for this campo rupestre endemic species. Our results also indicate that heat tolerance, especially the ability to withstand stressful temperatures for a long time, is an important parameter that differentiates the ecological strategies of these bromeliads species.

Morphophysiological Plasticity in Epiphytic Bromeliads Across a Precipitation Gradient in the Yucatan Peninsula, Mexico

“…These physiological differences are also evident in the NMDS analysis, which showed a segregation of tank and atmospheric species according to the second axis. This same pattern (high plasticity in acidity and low in RWC) was found in Chaves, Leal, and de Lemos-Filho (2018) for three tank species. Tank species may have higher carbon assimilation when water in the tank provides a stable water source but then suppress carbon gain through stomata closure to maintain stable RWC values when the tank is dry (Adams & Martin, 1986; Graham & Andrade, 2004; Reyes-García, Griffiths, et al., 2008).…”

“…Low osmotic potential has been related to osmotic adjustment in the later species (Cach-Pérez, 2013). In general, the RDPI values reported here were similar or higher than those reported in other CAM epiphytes (Bromeliaceae, Chaves et al., 2018; Orchidaceae, de la Rosa-Manzano et al., 2017) but lower than those reported for C 3 epiphytes (with the exception of T. balbisiana ; Pires, de Almeida, Abreu, & da Costa Silva, 2012).…”

“…The calculation of a plasticity index may be a way to measure the magnitude of these physiological and morphological changes, which can help to understand the strategies followed by plants to cope with environmental variations. It has been proposed that species with wide distribution will show larger phenotypical plasticity than species with restricted distribution, due to their exposition to a wide range of environmental heterogeneity (Chaves, Leal, & Lemos-Filho, 2018; Sultan, 2001; Valladares et al., 2006). There is an increasing interest in plant plasticity given the urgency to predict the response of species to climate change (Potvin & Tousignant, 1996; Rehfeldt, Wykoff, & Ying, 2001).…”

High resilience to extreme climatic changes in the CAM epiphyte Tillandsia utriculata L. (Bromeliaceae)

“…The RDPI values of both populations of T. utriculata confirmed the high plasticity of the species (Fig. ), as the values were in general higher than that previously observed in most epiphytic species (Chaves et al , de la Rosa‐Manzano et al , Cach‐Pérez et al ; but similar values reported for Miltonia flavescens by Pires et al ) and similar to that of invasive woody and herbaceous species (Godoy et al ). Studies involving RDPI values have shown that not all variables are equally divergent within a species, but some tend to be more conservative.…”

Responses of Neotropical Savannah Plant Species to Abiotic Stresses: A Structural and Functional Overview

“…Model-based studies predict changes in plant species distribution and loss in areas with greater biodiversity due to increased worldwide global temperature [97][98][99][100], also affecting the Neotropical savannah [100,101]. Chaves et al [102], in a study of a restricted plant species from the rupestrian field, showed that although some plants were no longer sensitive to the increase in temperature, they showed lower thermal tolerance and less plasticity compared to plant species of wide distribution, with a possible impact of global climate changes on this species. A recent modeling study evaluating the effect of habitat loss and climate change on 2,354 species of restricted distribution (including the Neotropical savannah) showed that 70 to 85% of them are at high risk of extinction [103].…”